The union says the oil and gas industry's report is flawed as it was only a survey of some companies and did not look at their public finance data.

The Maritime Union has hit back at the oil and gas industry over concerns high wages are making Australia's liquefied natural gas industry uncompetitive.

In a new report, the union has accused employers of playing politics and overstating the impact of rising wages on the viability of shipping companies which supply oil and gas platforms, lay pipes and do underwater exploration.

The union commissioned economic forecaster, BIS Shrapnel, to look into a report by Deloitte Access Economics on companies which support offshore oil and gas exploration known as the offshore oil and gas marine support sector.

The Deloitte report concluded that the firms' profitability had fallen and strong wage increases would threaten the viability of the ship operators.

It said that over the last five years, wages and total expenses doubled while revenue increased by only 50 per cent.

Employers group, the Australian Mines and Metals Association (AMMA), commissioned the Deloitte report.

But BIS Shrapnel says the Deloitte report was flawed because it surveyed five out of 19 vessel operators instead of looking at public data on their finances.

BIS Shrapnel says a review of annual reports and investor presentations for three vessel operators showed revenue growth of 200 per cent from 2007 to 2012 compared to wage growth of 50 per cent which "strongly refutes the claim that wage growth is outpacing revenue growth".

The union is pushing for a 6 per cent annual pay rise over three years.

Scott Barklamb from AMMA says the industry cannot afford it.

"What is of concern is when you see possible wage increases doubling in 10 years for some occupations," he told the ABC.

MUA report disputes wages are a major driver of project costs

The oil and gas industry says wages are a major driver of costs.

But the union's report found that wage costs for support ship workers were just 0.25 per cent of the cost of Australia's biggest resources development, the Gorgon gas project.

The union's report also disputes assertions that Australia is pricing itself out of the global LNG industry amid an estimate by consulting firm, McKinsey, that new LNG projects in Australia are 30 per cent more expensive than in Canada or East Africa.

It says as the Australian dollar falls the cost of local gas projects and the competitive gap will also decline.

Kevin Gallagher runs engineering firm, Clough, which has contracts on major resources projects.

He says Australia is facing tough competition from other LNG producing countries because of its higher wages.

"With the wage inflation we've seen over the last few years that's got to make it more difficult and it has made it more difficult to attract investment to Australian projects," Mr Gallagher said.